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United States Patent |
5,139,705
|
Wittpenn, Jr.
,   et al.
|
August 18, 1992
|
Compositions employing nonionic surfactants
Abstract
A mild, non-irritating surfactant composition, which includes an anionic
surfactant, an amine oxide, a nonionic surfactant having a relatively low
melting point, and a nonionic surfactant having a high melting point
relative to the low melting point nonionic surfactant.
Inventors:
|
Wittpenn, Jr.; John R. (57 Poinsettia Ave., Weymouth, MA 02188);
Giovanoni; Richard L. (220 Richmond St., East Taunton, MA 02718)
|
Appl. No.:
|
301390 |
Filed:
|
January 25, 1989 |
Current U.S. Class: |
510/137; 510/136; 510/159; 510/423; 510/537 |
Intern'l Class: |
C11D 001/18; C11D 009/50 |
Field of Search: |
252/547,174.22
|
References Cited
U.S. Patent Documents
3943234 | Mar., 1976 | Roggenkamp | 252/142.
|
3950417 | Apr., 1976 | Verdicchid et al. | 252/545.
|
Primary Examiner: Clingman; A. Lionel
Attorney, Agent or Firm: Watson, Cole, Grindle & Watson
Parent Case Text
This application is a divisional application of application Ser. No.
034,043, filed Apr. 3, 1987 now issued as U.S. Pat. No. 5,000,868.
Claims
What is claimed is:
1. A mild liquid surfactant composition having good foaming characteristics
and such non-irritating characteristics that it is used on periocular
surface tissues, comprising:
(a) an anionic surfactant having high foaming properties and being mildly
irritating to human tissues, said surfactant being present in cleansing
quantities;
(b) a relatively low melting point nonionic surfactant;
(c) another nonionic surfactant having a high melting point relative to the
melting point of said low melting point nonionic surfactant,
(d) said low and high melting point nonionic surfactants together being
present in a total amount capable of reducing the irritant properties of
said anionic surfactant and of emulsifying or solubilizing body surface
physiologic debris, and individually being present in relative amounts to
adjust the viscosity of said resulting composition to a predetermined
value;
(e) an amine oxide in an amount sufficient to enhance the foaming
properties of the anionic and nonionic surfactants while further reducing
the irritating characteristics of the anionic surfactant;
(f) the pH of said composition being maintained substantially at
neutrality, at which said amine oxide is induced to act as a nonionic
surfactant rather than display the ionic properties it exhibits in an acid
medium.
2. A surfactant composition as claimed in claim 1, in which said relatively
low melting point nonionic surfactant melts at approximately 40.degree. to
44.degree. C. and said relatively high melting point nonionic surfactant
melts at about 50.degree. to 54.degree. C.
3. A surfactant composition as claimed in claim 1, in which said relatively
low and high melting point surfactants are present in a ratio of about
1:4.
4. A surfactant composition as claimed in claim 1, in which said relatively
low melting point nonionic surfactant is composed of ethoxylated glyceryl
cocoate.
5. A surfactant composition as claimed in claim 1, in which said relatively
high melting point nonionic surfactant is composed of ethoxylated glyceryl
tallowate.
6. A surfactant composition as claimed in claim 4, in which said relatively
high melting point nonionic surfactant is composed of ethoxylated glyceryl
tallowate.
7. A surfactant composition as claimed in claim 1, in which the ratio of
said low melting point nonionic surfactant to said high melting point
nonionic surfactant varies between about 1:1 to 1:8.
8. A surfactant composition as claimed in claim 1, in which the ratio of
said anionic surfactant to the total of said low melting point and said
high melting point nonionic surfactants varies between about 1:1 to 1:4.
9. A surfactant composition as claimed in claim 8, in which the ratio of
said anionic to the total of said low melting point and said high melting
point nonionic surfactants is about 3:5.
10. A surfactant composition as claimed in claim 1, in which the ratio of
said anionic surfactant to said amine oxide varies between about 1:0.1 to
1:4.
11. A surfactant composition as claimed in claim 1, in which the ratio of
said anionic surfactant to said low melting point nonionic surfactant to
said high melting point nonionic surfactant to said amine oxide is
approximately 3:1:4:2.
12. A mild liquid surfactant composition having good foaming
characteristics, comprising:
(a) an anionic surfactant having high foaming properties and being mildly
irritating to human tissues, said surfactant being present in cleansing
quantities;
(b) a relatively low melting point nonionic surfactant which has a melting
point in a range of about 40.degree. to 44.degree. C.;
(c) another nonionic surfactant having a high melting point relative to the
melting point of said low melting point nonionic surfactant, the melting
point of said high melting nonionic surfactant being in a range of about
50.degree. to 54.degree. C.;
(d) said low and high melting point nonionic surfactants together being
present in a total amount capable of reducing the irritating properties of
said anionic surfactant and of emulsifying or solubilizing body surface
physiologic debris, and individually being present in relative amounts to
adjust the viscosity of said resulting composition to a predetermined
volume, the ratio of said anionic surfactant to the total amount of said
nonionic surfactants varying from about 1:1 to 1:4; and
(e) an amine oxide in an amount sufficient to enhance the foaming
properties of the anionic and nonionic surfactants while further reducing
the irritating characteristics of the anionic surfactant, the ratio of
said anionic surfactant to said amine oxide varying from about 1:0.1 to
1:4;
(f) the pH of said composition being maintained substantially at
neutrality, at which said amine oxide is induced to act as a nonionic
surfactant rather than display the ionic properties it exhibits in an
oxide medium.
Description
BACKGROUND OF THE INVENTION
The present invention relates generally to surfactant compositions. More
particularly, it relates to a surfactant composition which is composed of
a combination of surfactants that make it an effective cleansing agent,
but with non-irritating properties such that it is especially effective
for use on periocular and ocular surface tissues.
For some time a desirable surfactant product has been sought in which the
advantageous foaming properties of an anionic surfactant can be maintained
while avoiding the irritation to the skin that such surfactants normally
cause. The characteristic of irritating sensitive human skin and membranes
is particularly evident when the surfactant is to be utilized in the
vicinity of the human eye. Such surfactants or shampoos have previously
been utilized to help in the control of oily debris, cosmetics and
encrusted material that may form on the scalp and face. Yet there is
definite need for a surfactant composition for use in conditions requiring
good eyelid and eyelash cleansing.
An example of one such condition is acute and chronic blepharitis.
Blepharitis is an inflammation of the eyelids that arises in the glands
found at the base of the eyelashes (glands of Zeis and Moll) and just
behind the eyelashes (meibomian glands). These glands secrete an oily
lipid material (meibom), which is essential for maintenance of the normal
tear film on the ocular surface as well as the natural lubrication of the
eyelids. When these glands become inflamed or clogged by thickened
secretions, cosmetics, infection, or other causes not yet identified, the
surrounding tissues become inflamed. The resulting inflammation of the
eyelids and ocular surface is called blepharitis and can produce a variety
of symptoms of ocular dysfunction. These symptoms may include but not be
limited to any or all of the following: irritation, itching, burning,
dryness, tearing, redness of the eyelids and conjunctiva, filmy vision,
chalazion or hordeolum formation, and loss of eyelashes. Severe cases can
even produce corneal opacification and decreased vision.
The mainstay of present therapy for blepharitis is the combined use of warm
compresses and daily lid hygiene to clean the oily secretions, crusting
and other forms of debris which accumulate on the eyelids and eyelashes,
thereby exacerbating the inflammatory problem. Certain oral and topical
medications are then added to this primary therapy as needed in each
individual case. However, at present there is no cleansing surfactant
product specifically designed for use by the patient to clean the eyelids
and eyelashes. Therefore eye care professionals currently recommend the
use of mineral oil or mild hair shampoos. These shampoos must be diluted
by the patient with water to reduce the irritancy of the cleansing
component in the shampoo. Despite using dilute hair shampoos, many
patients develop a secondary ocular irritation from the cleansing agents,
themselves. These shampoos have the additional disadvantage of containing
dyes and/or perfumes which do not enhance the cleansing potential but may
act as ocular irritants.
Consequently, a desirable surfactant product combines the advantages of
foaming and cleansing properties of anionic surfactants with other
surfactants and pharmaceutical agents such that the resulting composition
is nonirritating to skin, periocular tissues and ocular surface tissue. It
is, therefore, a primary object of the present invention to provide such a
surfactant composition which maintains the foaming and cleansing
characteristics of an anionic surfactant, while at the same time
significantly ameliorating the irritating characteristics of such
anionics. This surfactant composition is suitable for use in those
conditions requiring daily lid hygiene such as blepharitis. This
surfactant composition has further utility as a nonirritating cleanser of
cosmetics. It is a further object to provide such a surfactant composition
that can be used to effectively clean skin, mucous membrane and ocular
surface tissue prior to invasive and noninvasive treatments while avoiding
the introduction of concomitant irritation. Finally, it is a further
object to provide such a surfactant composition which can be used to
cleanse nonbiological surfaces, which are then placed on or near the eye.
These and other objects of the present invention will become more apparent
to one of skill in this art from the summary and detailed description of
the invention provided hereinafter.
SUMMARY OF THE INVENTION
Our invention is, in its broad form, a mild, non-irritating surfactant
composition having good foaming characteristics. The composition comprises
an anionic surfactant with high foaming properties and only mildly
irritating to human tissues; non-ionic surfactants capable of reducing the
irritant properties of the anionic surfactant and also of emulsifying and
solubilizing physiologic debris, and an induced non-ionic surfactant which
enhances the foaming properties of the anionic surfactant while further
reducing the irritating characteristics of the anionic surfactant.
The induced non-ionic surfactant, as we use that term herein, may take the
form of an amine oxide, e.g., coco amido propyl oxide or lauryldimethyl
amine oxide or may take the form of an alkanolamide such as Witcamide
STD-HP manufactured by Witco Chemical Corp. of NY. The anionic surfactant
as used in the surfactant composition of the present invention may be a
sulfosuccinate, e.g., disodium laureth sulfosuccinate.
In one form of our invention, the nonionic surfactant is a blend of two
nonionic surfactants which, with respect to each other, have relatively
high and low melting points. Exemplarily, these melting points may be at
about 40.degree. to 44.degree. C. for the low melting point composition
and 50.degree. to 54.degree. C. for the high melting point composition. In
this way the use of two or more nonionic surfactants can be used to
balance the viscosity of the resulting composition. Generally, the two
compositions will be used together so that they will be present in
combination, in an amount somewhat greater than the amount of anionic
detergent utilized.
The surfactant composition of the present invent on will advantageously
utilize other materials that will, for example, provide antimicrobial
protection. Thus, other materials that may form part of the surfactant
composition that we regard as being our invention are disodium edetate,
which may be used to adjust the pH of the composition to about 6.7 to 7.5,
and benzyl alcohol.
DETAILED DESCRIPTION OF THE INVENTION
The composition of the present invention comprises an anionic surfactant.
While there are a wide variety of anionic surfactants suitable for use in
the present invention in a satisfactory manner, the surfactant selected
for the best mode is one that has the greatest degree of mildness in
contact with ocular or other sensitive tissues, yet supplies copious
foaming, preferably in the form of microbubbles. Such a high foaming
characteristic with a low degree of irritating properties has been
achieved by sulfosuccinates, and most specifically by disodium laureth
sulfosuccinate, a synonym for which is disodium lauryl alcohol polyglycol
ester sulfosuccinate. It is marketed by Sherex Co., of Dublin, OH, under
the trademark VARSULF SBFA-30 or by sulfate and sulfonates of ethoxylated
alkyl phenols such as Alipal marketed by GAF Corp. of Wayne, NJ. According
to the producer's literature, the composition has been evaluated for
primary eye irritation n rabbits. 15% and 10% solutions were rated
moderately irritating, while a 5% solution was given a mild irritancy
rating.
In the preferred embodiment of our invention, a plurality of nonionic
surfactants are utilized. The purpose of using such plurality of nonionic
surfactants is to do so in a ratio that will permit an adjustment of the
vicosity of the resulting composition in water to meet the specific use
required. The requirement of the nonionic surfactants is that they be
capable of reducing the irritating properties of the anionic surfactant,
and also be capable of emulsifying and solubilizing physiologic debris
from the surface of the body, particularly oily secretions and
collarettes, which are crusted deposits that can form around the eyelash
base.
In the best mode of my invention, we prefer to utilize both a relatively
low melting point and a relatively high melting point nonionic surfactant.
Surfactants that have been found to be well suited for use in the present
composition are a series of nonionic, anti-irritant surfactants which
generally are ethoxylated mono and diglycerides derived from coconut oil
and tallow or a series of nonionic, anti-irritant surfactants which
generally are alkanolamides such as coco monoethanol amide marketed as
Carsamide CMEA by Lonza, Inc. of Fair Lawn, NJ and/or lauric
mono-isopropanolamide marketed as Cyclomide LIPA by Cyclo Chemical Corp.
of Miami, FL. Such nonionic surfactants are non-toxic and nonirritating to
the skin or eye at the 100% active level and in aqueous dispersions.
Further, they impart anti-irritating properties to anionic surfactants,
including sulfosuccinates. Moreover, although the non-ionics are only
moderate foamers by themselves, they do not depress the foam of high
foaming anionic. By utilizing both relatively low and relatively high
melting point nonionics, the viscosity of the finished system can be
controlled without the use of thickeners that are themselves potentially
irritating. Further, the nonionic surfactants should be good emulsifiers
and solubilizers for cosmetic creams and lotions where low irritation
properties, emollient and viscosity control characteristics are highly
desirable.
In the preferred embodiment of our invention, we utilize a combination of
two nonionics, one of which is an ethoxylated glyceryl monococoate, as the
relatively low melting point nonionic, and ethoxylated glyceryl
monotallowate as the relatively high melting point nonionic. The melting
point of the monococoate is about 42.degree. C.; that of the monotallowate
is about 53.degree. C. When used in predetermined proportions, the
combination of these two nonionic surfactants with the remaining
ingredients in an aqueous solution may be manipulated so as to achieve
desired viscosity, in addition to the other desirable properties of the
nonionics. These nonionic surfactants are sold, respectively, under the
trademarks VARONIC LI-67, an ethoxylated glyceryl monococoate which has
the relatively low melting point, and VARONIC LI-420, an ethoxylated
glyceryl monotallowate which has the relatively high melting point. Both
VARONIC polymers are sold by Sherex Chemical Co., Inc. of Dublin, OH.
The third ingredient of the composition that forms the basis of the present
invention is what we term: an induced nonionic surfactant. Typical of an
induced nonionic surfactant is an amine oxide, which is an effective foam
stabilizer for anionic surfactants, particularly for fatty alcohol
sulfates, alcohol ether sulfates and alpha olefin sulfonates. These amine
oxides are noted for their mildness and ease of handling. In neutral or
slightly alkaline systems amine oxides behave in the manner of nonionic
surfactants; hence the designation, induced nonionic surfactant. In
slightly acid systems, they assume mild cationic characteristics, although
they remain compatible with anionic surfactants.
By stabilizing the foam of the anionic, the induced nonionic enables the
cleansing action of the anionic to continue throughout the scrubbing
period. Moreover, it aids in assisting a rinse-off of suds of the anionic
at the end of the scrubbing period. Further, the induced nonionic at a pH
for the entire composition of approximately 7 exhibits the properties of a
nonionic surfactant, thereby enhancing the foaming properties of the
product and acting to reduce potential irritancy of the anionic. Further,
since the induced nonionic has a change in viscosity building effect in
accordance with the pH of the final product--such viscosity increases as
the pH of the product decreases--a final adjustment of pH at or about
neutrality can serve to increase or decrease the viscosity of the final
product according to the specific end use to which it is put. Thus, where
a somewhat gelatinous material is desired for application, e.g., to
cleansing pads, the viscosity of the present composition can be increased
by adjusting to the pH to somewhat below 7, whereas in a solution to be
applied on or near the ocular surface, the pH might be maintained at or
slightly above 7.
The most preferred induced nonionic, surfactant for use in the present
composition is an amine oxide. In the best mode of our invention, we
utilize cocoamido propylamine oxide. Such a composition is presently sold
by Sherex Co. under the trademark VAROX 1770. This specific amine oxide is
substantially non-irritating, and since the entire composition is intended
to be substantially non-irritating to sensitive tissues, an amine oxide
should be selected which has a very low level of irritancy.
Other materials that form part of the best mode of the present invention
are commercially available. Thus, disodium edetate, or ethylene diamine
tetracetic acid disodium salt, functions as an anti-microbial agent and
also as a pH adjuster. It acts to reduce the pH of the composition to
about 7.0 to 7.2 from a range of about 7.5 to 7.8. Disodium edetate is a
commonly used preservative in ophthalmic preparations intended for
installation directly into the eye. Using disodium edetate to adjust pH
obviates the need of adding other agents that have obviously irritating
properties, e.g., hydrochloric acid or sodium hydroxide, for that purpose.
In the best mode of the present composition, benzyl alcohol is also
utilized. It functions to enhance the anti-microbial action of the
disodium edetate, and has its own such action enhanced by the edetate.
Benzyl alcohol is especially effective in killing or inhibiting the growth
of fungi. Of course, all the ingredients of the subject composition have
an inate ability to kill and/or inhibit microbial growth, either by the
destruction of cell walls, as in the case of surfactants, or by directly
inhibiting metabolic functions of the microbes, as with disodium edetate
and benzyl alcohol.
Regarding the quantities utilized of the various materials that are part of
the present formulation, to some degree the amount utilized will depend on
the desired viscosity of the final composition and the pH thereof. It has,
however, in the best mode been found to be most desirable to use
quantities so that of the various ingredients will be present in the
following amounts by weights: anionic--3%; low melting point nonionic--1%;
high melting point nonionic--4%; induced nonionic--2%; disodium
edetate--0.05%; benzyl alcohol--0.5%; and water for injection--the
remaining 89.45%.
While these various quantities of ingredients represent the best mode of
the present invention as presently known to us, it will be obvious that
variations thereof can occur in accordance with a range of non-irritating
properties and a range of pH and viscosity. For example, when the
composition of the present invention is to be used as a makeup remover,
the importance of the non-irritating properties of the composition will
still be significant, but not as great as if the composition is to be used
on or near ocular surfaces. Thus, the ratio of anionic to total nonionic
(excluding induced nonionic), can vary from about 1:1 to 1:4, with the
preferred ratio being about 3:5 or 1:1.67. However, these are only
desirable ranges and, for particular uses, the ranges may be different.
With regard to amounts of relatively low to relatively high melting point
nonionics, the range can be from 1:1 to 1:8, with 1:4 presently being
preferred. The ratio of anionic to induced nonionic will vary
advantageously between about 1:0.1 to 1:4, with 1:.67 presently preferred.
Quantities of disodium edetate and benzyl alcohol are, as indicated,
preferred in quantities of about 0.05 and 0.5%, respectively, of the final
solution, which in the most preferred form includes slightly less than 90%
water.
The range of pH is about 6.7 to 7.5, more preferably 7.0 plus or minus 0.2.
However, for uses where a higher viscosity is desired, the range may be
slightly lower, although not so low as to increase substantially the
irritant properties of the final composition.
The present process utilized to manufacture the product that is the subject
of the best mode embodiment hereof, is to heat all four surfactants in a
suitable vessel until they are liquified, being careful not to exceed a
temperature greatly above that of the relatively high melting point
nonionic which, in the preferred form of monotallowate, has a melting
point of about 53.degree. C. In another vessel about 85% of the formula
amount of water for injection, which is either deionized, membrane
filtered or distilled, is heated to the same temperature as the surfactant
phase. One phase is then added to the other with rapid mixing, and after
the turbidity clears, the solution is allowed to cool to room temperature
with constant, slow mixing. The pH of the solution at this stage of
manufacture was found to be about 7.8. Then disodium edetate is added and
slow mixing continued until the edetate had totally dissolved and the pH
was approximately 7.0. Finally, the benzyl alcohol is added and mixing
continued until the solution cleared. Thereafter, the remaining water to
bring the total weight to 100%, which in this case would be the final 4.5%
water, is added.
After the composition had been produced, it underwent a series of tests to
determine whether it was suitable for application to human tissues.
Primary eye irritation testing was made, and no irritation was noted
during the standard 28-day testing period. In skin maximization allergy
testing, no irritation was noted during the standard 35-day testing
period. Microbial limits testing was performed to ensure that no pathogens
were present, and preservative challenge testing was performed to ensure
that the composition in solution met USP requirements as a solution that
can inhibit and/or kill microbes upon repeated exposure to the solution.
As formulated, a solution according to the present invention has the
ability to ameliorate certain skin conditions associated with blepharitis,
as well as rosacea and seborrhea, upon repeated application of warm
compresses combined with daily lid hygiene with the present invention.
Such lid hygiene was conducted by pouring a few drops of solution of the
composition on a cleansing pad or equivalent item that provides a matrix
for the product, rubbing the pad between the fingers to work up a
microbubble lather, using the pad to remover oily debris or cosmetics from
the eye area, rinsing the eye area with clean, warm water, and gently
drying same. In this manner the present composition can perform its
function as a gentle, non-irritating cleansing agent for human tissues,
and particularly for use on human tissues surrounding the eye, or even on
the ocular tissue, itself. The present composition is satisfactory to act
as a cleanser for nonbiological surfaces which are then placed on ocular
surfaces.
It will be apparent to those of skill in this art that certain alterations
and modifications of the present composition as disclosed hereinbefore may
be made. As to all such obvious alterations and modifications, we desire
that they be included within the purview and spirit of our invention,
which is to limited only by the scope, including equivalents, of the
following, appended claims.
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